微束等离子体弧焊电弧物理特性多场耦合分析

根据磁流体动力学方程组,建立了微束等离子电弧模型,使用有限元分析软件COMSOL进行模拟计算。结果表明,电弧中心温度分布从钨针至焊件整体呈"毛笔"状,其中,喷嘴下方电弧形态呈"钟罩"形,在焊件上温度分布符合高斯分布特征;电弧等离子体在喷嘴内部速度较大,离开喷嘴后,其方向由喷嘴内的竖直向下逐渐变为到达工件时的向四周扩散;电流由焊件表面流出,经过弧柱区域流入钨针下端面,在钨针下端面附近取得最大值;电弧磁通密度分布呈"肺叶"状。最后进行了相应的熔焊试验,试验过程中拍摄的电弧轮廓与仿真电弧形态基本一致。

Multi-field coupling analysis of arc physical properties in micro-plasma welding

A model of micro-plasma arc is established based on the Magnetohydrodynamics equations, which are solved with the finite element analysis software COMSOL. The results show that the temperature distribution of the arc center is in a “brush” shape from the tungsten needle to the workpiece as a whole, where the arc temperature distribution under the nozzle is in a “bell” shape, and the temperature on the workpiece conforms to the Gaussian distribution; the arc plasma has a large velocity inside the nozzle. After leaving the nozzle, its direction gradually changes from vertical downward in the nozzle to the surrounding direction when reaching the workpiece; the current flows out from the surface of the workpiece and flows into the lower end face of the tungsten electrode through the arc column, and the maximum value is obtained near the lower end face of the tungsten electrode; the flux density distribution of the arc is in a “lobes” shape. Finally, the fusion welding test was carried out, and the arc profile captured during the test was basically the same as the simulated arc shape.